[y4mi]

Because i struggled to understand what you meant I'd like to rephrase it:

It matches only if the regex is applied to a singular word. It's not going to match if there is a sentence or any apostrophe etc, which is implied to be valid input because it supposedly matches "all words".

[Filligree]

That’s easy to misunderstand. And if humans have trouble with it, then I won’t blame the poor AI.

Getting an AI to ask clarifying questions would be useful, of course…